Smokestack aerosol gas purifier



July 14, 1970 A. M. MARKS SMOKESTACK AEROSOL GAS PURIFIER Filed Oct. 2, 1968 United States Patent 3,520,662 SMOKESTACK AEROSOL GAS PURIFIER Alvin M. Marks, 153-16 10th Ave., Whitestone, N.Y. 11357 Filed Oct. 2, 1968, Ser. No. 764,404 Int. Cl. B01j 1 /00; B03c 5/00 US. Cl. 23-284 8 Claims ABSTRACT OF THE DISCLOSURE BACKGROUND OF THE INVENTION This application is related to an application filed Oct. 3, 1966, Ser. No. 583,749, entitled Charged Aerosol Fume Suppressor and Method, Alvin M. Marks, applicant.

It has been the practice in the past, to employ electronic precipitators and scrulbbers in an effort to reduce the foreign material emanating from smokestacks as a result of combustion. However, such devices have only been able to remove a small proportion of the noxious material and are unable to handle extremely small particles and gases. The present invention employes the principles of the charged aerosol for the purpose of removing substantially all of the products of combustion and rendering harmless those noxious gases which normally emanate from the stack, by means of absorption of the noxious gases into the charged aerosol liquid or by chemical reaction with reactants carried within the charged aerosol liquid.

SUMMARY OF THE INVENTION The present invention employs a chamber carried within the discharge end of the stack through which the products of combustion are led. A charged aerosol producing assembly is disposed within the stack so that the gases of combustion are caused to pass through the charged aero sol. Charge droplets forming the aerosol absorb, react, entrap, and entrain the products of combustion as they are led past the aerosol producing device. The charged droplets are then caused to coalesce upon the surface of the receptacle 'from which they are drained off while still carrying the products of combustion. The air which emerges from the stack is substantially free of noxious material.

DESCRIPTION OF THE DRAWINGS In the accompanying drawings forming a part hereof corresponding parts have been given identical reference numerals and in which drawings;

FIG. 1 is a view in side elevation, partly broken away of the top of a smokestack showing the present invention,

FIG. 2 is a view similar to FIG. 1 illustrating an alternate form of aerosol generating apparatus,

FIG. 3 is a fragmentary cross sectional view of the charged aerosol forming structure of FIG. 2.

DESCRIPTION OF PREFERRED EMBODIMENTS Referring to the drawing and particularly to FIG. 1, 10 indicates a smokestack or chimney having a gas tight cover 11 secured to the outlet end thereof. An emission conduit 12 is carried by the cover so as to extend outwardly thereof into the atmosphere and downwardly into the stack 10 for a short distance.

A cup-shaped deflector 13 is positioned within the stack "ice 10 and underlies the inner end of the emission conduit 12. The deflector 13 is equally spaced from the interior of the stack by means of brackets 14. A weather cap 15 is mounted above the end of the emission conduit 12 by means of clips 16.

A small fan 17 driven by a motor 18 is carried within the discharge end of the emission conduit 12 to aid in the passage of gas from the stack to the atmosphere when natural draft is inadequate.

A series of concentric annular pipes 19, 20, are disposed around the emission conduit 12 a short distance above the bottom 21 of the said conduit. The pipes 19, 20, are connected to an inlet fluid supply line 22 as indicated at 23. A plurality of small nozzles 24 having very small orifices therein extend downwardly from the pipes 19, 20, in the direction of the bottom of the deflector member 13. The nozzles 24 may be in the nature of hypodermic needles communicating with the interior of the pipes 19, 20.

Spaced from the bottom of the nozzles 24 is a charge plate 25 made of some suitable electrically conductive material and provided with a series of apertures 26 therein. The apertures 26 underlie each of the nozzles 24 so that the aerosol droplets emitted from the nozzles can pass through the apertures. The charge plate 25 is mounted upon a ring 27 which is coaxially supported by insulators 28 secured to the inner surface of the deflector 13.

Voltage is supplied to the charge plate 25 from a DC exciter 29 having an output of between 5 to 10 kv. A lead 30 is led from the exciter 29 through the cup-shaped deflector 13 to the charge plate 25'. An insulator 31 is disposed around the lead 30 as it passes through the deflector 13.

In the operation of the device shown in FIG. 1, the products of combustion indicated by the arrows 32 rise upwardly through the stack 10 until they are blocked by the cover 11. The products of combustion then flow downwardly into the cup-shaped deflector 13 passing the nozzles 24. A small amount of liquid such as water is fed into the pipes 19, 20, through the supply line 22 under a small amount of pressure. The pipes 19, 20, and the supply line 22 are grounded and the charging plate 25 is at a positive or negative voltage relative to the said pipes. As a result, a strong electric field is established between the nozzles 24 and the charge plate 25. As the liquid emerges from the nozzles the drops of water break up into billions of sub-micron charge droplets under the effect of the electric field. It will be understood that when the charge plate is positive the droplets are negatively charged. Conversely, the charge plate could be negative giving a positive charge to the droplets. The charge droplets collide with the particles in the gas stream comprising the products of combustion moving through the deflector 13. The gases in the products of combustion are absorbed into the minute water droplets constituting the charged aerosol which was formed between the nozzles and the charge plate 25.

The combined charged droplets and products of combustion which are now in the form of minute charge droplets 33 mutually repel each other and coalesce upon the inner surface 34 of the cup shaped deflector 13. The coalesced droplets flow to the bottom of the deflector and are led out through a discharge pipe 35 which communicates with the interior of the deflector 13. The purged gases continue up the emission conduit 12, past the fan 17 and out of the assembly into the atmosphere.

It is within the purview of the present invention to use various liquids besides water in the formation of the aerosol. Thus, for example, distilled, tap, or salt water may be employed resulting in a 99% absorption of S0 for air having 1000 p.p.m. of S0 flowing at 560 cc./min. using an aerosol rate of 1 cc./min. For some gases a reactant may be included in the water as for example, an oxidiser such as potassium mono persulfate where carbon monoxide is to be absorbed, or an alkali such as NaOH, where a larger volume of S is to be absorbed than is possible by absorption only.

As an example, with an airflow of about c.f.m. it has been found that the electric power requirements are about 27 watts/ sq. ft. of cross-section.

Referring to FIG. 2 there is shown a second embodiment of the present invention which differs from that hereinabove described in connection with FIG. 1, in that the aerosol forming structure consists of a porous pipe 40 disposed around the emission conduit 12. The porous pipe 40 is supplied with liquid by means of the supply line 22 in the manner previously described in connection with FIG. 1. The porous pipe or tube 40 may comprise a porous ceramic having pores of a diameter varying from about 1 micron to 100 microns. Another form of porous tube may comprise metal tubes formed by the technique of powdered metallurgical processes and sintering to form a structure having the porosity in the ranges given above. Concentric with the porous pipe 40 is a metal screen 41 supported concentrically by means of an insulating ring 42 secured to the porous pipe and supported by the deflector 13. The screen 42 constitutes a mesh electrode for the purpose of establishing an electric field between the screen 41 and the porous pipe 40. Within this electric field the aerosol is charged and formed as hereinabove indicated following which it collides with the particles in the gas stream and absorbs the noxious gases.

In all other respects the operation of the embodiment shown in FIG. 2 is identical to that shown and described in connection with FIG. 1.

Having thus fully described the invention, what is claimed as new and desired to be secured by Letters Patent of the United States is:

1. A Smokestack aerosol gas purifier comprising in combination with a smokestack, a gas tight cover secured to the discharge end of the stack, a cup shaped deflector within the stack spaced from the inner surface thereof and below the cover, an emission conduit carried by the cap and extending outwardly thereof into the atmosphere at one end and into the deflector at the opposite end, a source of fluid communicating with the interior of the deflector, an aerosol droplet forming means connected to the fluid source, an aerosol droplet charging means within the stack disposed around the emission conduit, a voltage source connected to the charging means, where- 4 by the products of combustion traversing the deflector are entrained by the charged aerosol droplets and the droplets caused to coalesce and become discharged upon the deflector and means to lead the coalesced droplets out ofthe deflector.

2. A device according to claim 1 in which the current source comprises a 5 to 10 kv. DC exciter.

3. A device according to claim 1 in which the fluid source includes a reactant for the products of combustion.

4. A device according to claim 1 in which the aerosol forming and charging means comprises a series of concentric pipes, a plurality of fluid discharge nozzles extending from said pipes, a source of liquid under pressure connected to the pipes and a charging plate spaced from the nozzles.

5. A device according to claim 4 in which the charging plate is formed with a plurality of openings underlying and corresponding to the number of nozzles and the nozzles are in the form of hypodermic needles.

6. A device according to claim 1 in which the aerosol forming and charging means comprises a porous pipe disposed around the emission conduit within the deflector, a source of liquid under pressure connected to the pipe and a charging grid around the porous pipe between the said pipe and the wall of the deflector.

7. A device according to claim 6 in which the charging grid is in the form of a screen supported by an electrically insulating ring carried within the deflector.

8. A device according to claim 6 in which the porous pipe is formed with openings having a size of the order of 1 to 100 microns in diameter.

References Cited UNITED STATES PATENTS 1,905,993 4/1933 Buff 122 X 1,964,794 7/1934 Gilbert 23284 2,207,576 7/1940 Brown 55-10 2,357,354 9/1944 Penney. 2,935,375 5/1960 Boucher 23260 X 3,331,192 7/1967 Peterson 55--107 JOSEPH SCOVRONEK, Primary Examiner US. Cl. X.R. 

